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<h2>SeparateFields</h2>
<p><code>SeparateFields </code>(<var>clip</var>)</p>
<p>
NTSC and PAL video signals are sequences of fields, but all capture cards that
I'm aware of capture two fields at a time and interlace (or "weave") them into
frames. So frame 0 in the capture file contains fields 0 and 1; frame 1 contains
fields 2 and 3; and so on. <code>SeparateFields</code> takes a frame-based clip
and splits each frame into its component fields, producing a new clip with twice
the frame rate and twice the frame count. This is useful if you would like to
use <code><a href="trim.htm">Trim</a></code> and similar filters with
single-field accuracy.</p>
<p>
<code>SeparateFields</code> uses the field-dominance information in the source
clip to decide which of each pair of fields to place first in the output. If
it gets it wrong, use <code><a href="complementparity.htm">ComplementParity</a></code>,
<code><a href="parity.htm">AssumeTFF</a></code> or
<code><a href="parity.htm">AssumeBFF</a></code> before <code>SeparateFields</code>.</p>
<p>
From version 2.5.6 this filter raises an exception if the clip is already field-based.
You may want to use <code><a href="assumeframefield.htm">AssumeFrameBased</a></code>
to force separate a second time. Prior versions did a no-op for materials that was
already field-based.</p>
<p>
<kbd>$Date: 2005/10/03 16:31:31 $</kbd></p>
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